Drag racing is a type of vehicle competition in which the vehicle is driven over a relatively short course, usually one-fourth of a mile, from rest, the object being to cover the course in the shortest possible time. Drag racing machines are highly specialized having highly tuned engines which rotate at speeds in excess of 9,000 revolutions per minute and are equipped with many specialized components such as transmissions, shifting mechanisms and suspension systems. It is common for a good machine in the hands of a skilled driver to cover the course of one-fourth of a mile in less than ten seconds and to achieve speeds in excess of 160 miles per hour.
Drag racing vehicles are usually equipped with four or five speed manual transmissions and it is common for a skilled driver to take the machine through three gear changes during the first four seconds of a heat. Thus at the end of four seconds, the driver may shift from third to fourth gear in the vehicle while it is traveling at a speed of about 130 miles per hour and the engine is rotating at a speed of 9,000 RPM. Most drag race drivers change gears in the usual manner, that is by de-clutching, moving the gear shift lever, and reengaging the clutch. These operations require about 0.15 seconds when carried out by a skilled driver and during this interval, the engine of a vehicle will not be transmitting torque to the drive shaft. Also, during changing, the driver maintains engine speed with the accelerator and sometimes has difficulty getting the vehicle into the next gear because of racing of the engine beyond the speed he desires.
It has long been recognized that gears can be changed without de-clutching with some transmissions and by the exercise of a high degree of skill on the part of the driver. One type of transmission produced by Doug Nash Equipment and Engineering Corporation, 36,360 Ecorse Road, Romulus, Michigan which is used to drag racing can theoretically be changed without de-clutching but there is a serious danger of damaging the transmission if this is done and most drivers prefer to de-clutch during shifting. It has also been recognized that gear changing is facilitated if the ignition system is deenergized and it has been suggested that gears could be changed in drag racing competition if the ignition system could be deenergized during the shifting operation. The prior U.S. Patents noted above disclose several types of mechanisms for deenergizing the ignition system during gear changing such as switches which are opened when the gear shift lever is moved. These prior art devices may be satisfactory for some driving conditions but they would be totally unsuited for the extreme conditions which exist in drag racing competition. The extremely high speeds achieved and the acceleration which the machines undergo causes considerable vibration which in turn would interfere with conventional mechanical switches on, or associated with, the gear shift lever. The risks of malfunction with such devices are so great that drivers do not choose to take the chance of using such devices for fear of failure which of course would prevent them from finishing a heat. The present invention is directed to the achievement of a gear shift lever having signal generating means therein which is positive in its action, completely reliable, and which can be used by the driver without distraction during a gear changing operation.
A preferred embodiment of the invention comprises a gear shift lever having a knob or handle on its end, the knob having an arm extending therefrom which is received in a recess in the upper end of the lever. The arm is pivoted in a manner which permits the arm and knob to move relative to the lever in the to and fro directions of movement of the gear shift lever when gear ratios are changed. The arm and knob are coupled to the gear shift lever when in their forward or rearward positions by means of detents which are releasable upon application of a force to the knob which is less than the force required to move the lever and shift gears. Thus, when the driver pushes or pulls the knob, he first moves the knob and arm relative to the lever and then he moves the lever to the position of the gear he is shifting into. The signal generating means is provided in the form of a light bulb and light detector in the lever. Light from the bulb is blocked from impinging on the detector when the arm and knob are in either of their extreme positions however, when they are moved from one position to the other light is permitted to impinge on the detector by virtue of a small hole in the arm. The detector produces a pulse or signal which is transmitted to a control circuit forming part of the ignition system of the vehicle. The control circuit in turn deenergizes the ignition system for a very brief interval while the gear lever is being moved. As a result, gears are changed under very low torque or no torque conditions and the driver need not de-clutch.